Generally, existing brake rotors include solid, non-venting rotor designs and venting designs, as disclosed in U.S. Pat. No. 5,878,848 (vented). Accordingly, conventional ventilated brake rotors generally include a pair of mutually spaced-apart annular disks that present two opposed external braking surfaces for engaging brake pads under a clamping operation of a braking actuator (brake caliper). The space between the disks typically includes a number of vanes with flow passages defined between each pair of adjacent vanes that extend between the disks from their inner diameter to their outer diameter. Rotation of the rotor causes the vanes to induce air flow through the flow passages from the inner diameter to the outer diameter of the disks, providing increased convective heat transfer from the rotor. Inlets for the vanes reside adjacent the external braking surface of the base of the rotor.
All rotors include a “hat”, which is used to mount and connect the brake disc to a wheel hub of a vehicle. In some disc brake rotor designs, the hat is integrally cast with the brake disc (rotor ring), and on other disc brake rotor designs, the hat is cast (or formed in some other method) separately, and then affixed to one side of the brake disc via fasteners, for example. However, such two piece brake rotor assemblies (i.e., a “hat” and “ring”) are used typically with heavier duty (e.g., racing, truck) applications, rather than on typical passenger cars.
Problems with prior art vented, two piece brake rotors include airflow, and heat transfer/dissipation of the rotor, for example. Specifically, in the prior art one-piece or two piece vented rotors, a hat is attached to a single side (the outboard side) of the rotor. Thus, the hat not only connects the brake disc to the hub but also acts as a heat sink for only one side of the rotor, which tends to lead to an unbalanced heat load on the disc brake rotor assembly. Such imbalanced heat distribution may further lead to rotor warping problems. In that same regard, airflow for the prior art rotor (either the one-piece or two piece brake rotor designs) vent inlets is restricted to air obtained from only the inboard side of the rotor. Thus, airflow is more limited.
Other problems also include those requiring directional, vented, brake rotors. For example, some prior art vented, disc brake rotors are rotationally specific; meaning, the rotor includes directional vanes which necessitates that the rotor rotate in one direction (e.g., clockwise, counterclockwise), in order for the vanes to operate optimally and provide more efficient airflow. However, this poses a drawback: if directional rotors are required, such as for heavy duty or racing applications on a vehicle, two different rotors must be provided—one for either side of the vehicle. Thus, two sets of tooling for the two different disc brake rotor assemblies must be constructed, thereby increasing manufacturing and inventory costs.